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Wildlife Managers (wildlife + managers)

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Life Sciences	91%

Selected Abstracts

Illegal meat hunting in serengeti: dynamics in consumption and preferences

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2008
Vedasto G. Ndibalema
Abstract Although wild meat is an important source of protein across Africa, patterns and reasons for its demand are poorly defined. A study was conducted on consumption by inhabitants of ten villages in five districts to the west of Serengeti National Park, Tanzania. The first sample of 600 villagers was systematically selected from village registers and surveyed using a questionnaire. The second sample consisted of 341 arrested illegal meat hunters. Nine species dominated by eland (Taurotragus oryx) and wildebeest (Connachaetes taurinus) in terms of meat taste and hunting vulnerability respectively were found to be most preferred or consumed. There were remarkable variations in consumption and preferences for each species amongst ethnic groups and localities. The economics of protein consumption indicates that wild meat is consistently cheaper and hence consumed more frequently than other meats. Respondents' topmost tasty meat , eland and topi (Damaliscus lunatus) , were rare; consequently, common species e.g. buffalo (Syncerus caffer) and wildebeest were the substitutes mostly consumed to supplement beef and fish. Presence of carnivore species on the menu clearly demonstrates survival techniques when availability changes. Wildlife managers should, therefore, bestow attention to the conservation of all species for a balanced ecosystem and species survival. Résumé Bien que la viande de brousse soit une importante source de protéines dans toute l'Afrique, le schéma et les raisons de cette demande sont mal définis. On a réalisé une étude sur la consommation des habitants de dix villages dans cinq districts situés à l'ouest du Parc National de Serengeti, en Tanzanie. Le premier échantillon de 600 villageois fut systématiquement sélectionné sur les registres du village et suivi au moyen d'un questionnaire. Le second échantillon se composait de 341 chasseurs illégaux qui avaient été arrêtés. On a découvert que neuf espèces, dominées par l'éland (Taurotragus oryx) et le gnou (Connochaetes taurinus) en ce qui concerne le goût et la vulnérabilitéà la chasse, avaient la préférence et étaient plus consommées. Il y avait de remarquables variations de consommation et de préférences pour chaque espèce selon les groupes ethniques et les localités. L'économie de la consommation de protéines indique que la viande de brousse est notablement moins chère et donc consommée plus fréquemment que les autres viandes. La viande la plus appréciée des répondants, l'éland et le topi (Damaliscus lunatus) était rare. Par conséquent, les espèces communes comme le buffle (Syncerus caffer) et le gnou étaient les substituts les plus consommées pour compléter le b,uf et le poisson. La présence de carnivores au menu montre bien les techniques de survie lorsque la disponibilitéévolue. Les gestionnaires de la faune sauvage devraient donc accorder leur attention à la conservation de toutes les espèces pour la survie des espèces elles-mêmes et d'un écosystème équilibré. [source]

Complex interactions among mammalian carnivores in Australia, and their implications for wildlife management

BIOLOGICAL REVIEWS, Issue 3 2005
Alistair S. Glen
ABSTRACT Mammalian carnivore populations are often intensively managed, either because the carnivore in question is endangered, or because it is viewed as a pest and is subjected to control measures, or both. Most management programmes treat carnivore species in isolation. However, there is a large and emerging body of evidence to demonstrate that populations of different carnivores interact with each other in a variety of complex ways. Thus, the removal or introduction of predators to or from a system can often affect other species in ways that are difficult to predict. Wildlife managers must consider such interactions when planning predator control programmes. Integrated predator control will require a greater understanding of the complex relationships between species. In many parts of the world, sympatric species of carnivores have coexisted over an evolutionary time scale so that niche differentiation has occurred, and competition is difficult to observe. Australia has experienced numerous introductions during the past 200 years, including those of the red fox (Vulpes vulpes) and the feral cat (Felis catus). These species now exist in sympatry with native mammalian predators, providing ecologists with the opportunity to study their interactions without the confounding effects of coevolution. Despite an increasing body of observational evidence for complex interactions among native and introduced predators in Australia, few studies have attempted to clarify these relationships experimentally, and the interactions remain largely unacknowledged. A greater understanding of these interactions would provide ecologists and wildlife managers world-wide with the ability to construct robust predictive models of carnivore communities, and to identify their broader effects on ecosystem functioning. We suggest that future research should focus on controlled and replicated predator removal or addition experiments. The dingo (Canis lupus dingo), as a likely keystone species, should be a particular focus of attention. [source]

Roads, Development, and Conservation in the Congo Basin

CONSERVATION BIOLOGY, Issue 6 2000
David Wilkie
Research in the Republic of Congo shows that roads established and maintained by logging concessions intensify bushmeat hunting by providing hunters greater access to relatively unexploited populations of forest wildlife and by lowering hunters' costs to transport bushmeat to market. Reconciling the contrary effects of roads on economic development and biodiversity conservation is one of the key challenges to wildlife managers in all nations. As the Democratic Republic of Congo prepares to reconstruct its almost completely collapsed road system, the government, donors, and conservation organizations have a unique opportunity to strategically prioritize investment in segments of the network that would maximize local and national economic benefits while minimizing adverse effects on forest wildlife. Resumen: La densidad de carreteras está estrechamente ligada al acceso a mercados, el crecimiento económico, la explotación de recursos naturales, la fragmentación del hábitat, la deforestación y la desaparición de tierras y vida silvestre. Investigación en la República del Congo muestra que las carreteras establecidas y mantenidas por las concesiones para tala de árboles intensifican la cacería al proveer a los cazadores un mayor acceso a poblaciones forestales de vida silvestre relativamente sin explotar y al disminuir el costo de transporte de la carne obtenida por la caza hacia el mercado. La reconciliación de los efectos contrarios de las carreteras en el desarrollo económico y la conservación de la biodiversidad es uno de los retos clave para los manejadores de vida silvestre en todas las naciones. A medida que la República Democrática del Congo se prepara para reconstruir su casi completamente colapsado sistema carretero, el gobierno, los donadores y las organizaciones no gubernamentales conservacionistas tienen una oportunidad única para priorizar estratégicamente las inversiones en segmentos de la red carretera que podrían maximizar los beneficios económicos locales y nacionales al mismo tiempo que se minimicen los impactos adversos sobre la vida silvestre forestal. [source]

Digital cementum luminance analysis (DCLA): a tool for the analysis of climatic and seasonal signals in dental cementum

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 1 2008
C. M. Wall-Scheffler
Abstract Cementum banding patterns have been used by archaeozoologists and wildlife managers for a number of decades to assess the season and age at death of mammalian populations. However, the observation and measurement of the nature of cementum banding, especially that of the final band, has proved to be difficult except under conditions of excellent preservation and advanced microscopy. The research presented here details a method for extracting luminance data from the banding patterns of cementum in order to quantify the optical properties of cementum tissue. By doing so, analysis of the relationship between cementum deposition and environmental variables is achieved. We present the results of a digital cementum luminance analysis (DCLA) on a sample of first molars from two species, Ovis aries, Soay and Capra ibex. The results indicate that significant relationships occur between seasonal temperature changes and cementum histology. Furthermore, we show that luminance values can be used to assess the geographical range of genetically similar populations. Our results demonstrate that the study of luminance is a vital tool for the quantitative study of dental cementum for both archaeological and ecological studies. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Estimation of immigration rate using integrated population models

JOURNAL OF APPLIED ECOLOGY, Issue 2 2010
Fitsum Abadi
Summary 1.,The dynamics of many populations is strongly affected by immigrants. However, estimating and modelling immigration is a real challenge. In the past, several methods have been developed to estimate immigration rate but they either require strong assumptions or combine in a piecewise manner the results from separate analyses. In most methods the effects of covariates cannot be modelled formally. 2.,We developed a Bayesian integrated population model which combines capture,recapture data, population counts and information on reproductive success into a single model that estimates and models immigration rate, while directly assessing the impact of environmental covariates. 3.,We assessed parameter identifiability by comparing posterior distributions of immigration rates under varying priors, and illustrated the application of the model with long term demographic data of a little owl Athene noctua population from Southern Germany. We further assessed the impact of environmental covariates on immigration. 4.,The resulting posterior distributions were insensitive to different prior distributions and dominated by the observed data, indicating that the immigration rate was identifiable. Average yearly immigration into the little owl population was 0·293 (95% credible interval 0·183,0·418), which means that ca 0·3 female per resident female entered the population every year. Immigration rate tended to increase with increasing abundance of voles, the main prey of little owls. 5.Synthesis and applications. The means to estimate and model immigration is an important step towards a better understanding of the dynamics of geographically open populations. The demographic estimates obtained from the developed integrated population model facilitate population diagnoses and can be used to assess population viability. The structural flexibility of the model should constitute a useful tool for wildlife managers and conservation ecologists. [source]

What controls woodland regeneration after elephants have killed the big trees?

JOURNAL OF APPLIED ECOLOGY, Issue 1 2009
Stein R. Moe
Summary 1Top-down regulation of ecosystems by large herbivores is a topic of active debate between scientists and managers, and a prime example is the interaction between elephants Loxodonta africana and trees in African savannas. A common assumption among wildlife managers is that a local reduction in elephant numbers will ultimately allow woodland to self-restore to a desired former state. Such regeneration is, however, dependent on the survival of seedlings of impacted tree species. We conducted a field experiment to investigate seedling predation in the elephant-transformed Chobe riparian woodland of northern Botswana. 2We planted seedling gardens in (i) complete exclosures that excluded all herbivores except small rodents and invertebrates, (ii) semi-permeable exclosures that excluded ungulates but included primates, lagomorphs, all rodents, gallinaceous birds, etc, and (iii) completely open plots. Seedlings were of two tree species decreasing in the area (Faidherbia albida and Garcinia livingstonei) and two that are increasing (Combretum mossambicense and Croton megalobotrys). 3After 9 months, seedling survival ranged from >75% for all species in the complete exclosure to <20% for Faidherbia albida in the open plots. Survival of all seedlings except C. megalobotrys declined precipitously in open plots during the dry season when invertebrates are largely dormant but when impalas Aepyceros melampus (locally abundant ungulates) increase the browse components of their diets. 4Seedling survival in the open plots was negatively related to local impala density but unrelated to that of any other browser. 5Synthesis and applications. Our findings relate to the current debate about managing elephants to restore southern African savanna landscapes to desired historical states. Various seedling predators, including the ubiquitous impala Aepyceros melampus, regulate the regeneration of trees from seedlings, and our experiments support the hypothesis that tall closed-canopy woodlands originate during episodic windows of opportunity for seedling survival. To artificially recreate such a window would require the decimation of seedling predators as well as elephants, which is impractical at the landscape scale. [source]

Simulating the East African wildebeest migration patterns using GIS and remote sensing

AFRICAN JOURNAL OF ECOLOGY, Issue 4 2004
Douglas E. Musiega
Abstract The Serengeti,Mara ecosystem in East Africa is a spectacular natural heritage endowed with diverse fauna and flora. The presence of the seasonally migrating wildebeest (Connochaetes taurinus) is a major boost for tourism. This migration however has enormous impacts to the ecosystem. Consequently efforts at monitoring the herd's migration trends and patterns remain a challenge to wildlife managers and ecologists in the region. In this paper, the relative influence of vegetation (normalized difference vegetation index), landscape and relief on herds migration routes are investigated and the migration routes simulated using GIS and remote sensing techniques. The results are compared with the annual mean route taken by the herds, as determined by radio tracking over the 1995,1997 period. Green vegetation availability is shown to be the major criterion in route choice. It is also shown that during the dry season phases of the migration (western trek, western corridor), the herd endures complex relief (complexity quantified based on slope and inter-visibility) in the search for greener grass. During the season of abundance (southern trek), relief becomes critical in making route choices, with herds avoiding difficult terrain, notwithstanding their relatively more abundant vegetation. The method proposed in this paper is viable for rapid prediction of approximate routes for the migrating wildebeest in different climatic conditions. Résumé L'écosystème Serengeti,Mara en Afrique Occidental est un patrimoine naturel spectaculaire, doté des divers variétés de flore et de faune. La présence du gnou migrateur (Connochaetes taurinus) représente un atout majeur pour le tourisme. Néanmoins, cette migration a un impact énorme sur l'écosystème. Par conséquence, la surveillance des tendances migratoires du troupeau est un défi constant pour les gérants et les écologistes dans la région. Dans cette enquête, l'influence relative de la végétation (NDVI), le paysage et le relief, sur les routes du migration prises par le troupeau ont étéétudiés, et simulés utilisant le Système d'Information Géographique (SIG) et des techniques de perception à distance. Les résultats sont comparés à la moyenne annuelle des routes prises par les troupeaux, déterminée par le repérage radio pendant la période allant de 1995 a 1997. Le disponibilité de végétation verte s'avère le déterminant majeur dans le choix du chemin. Il est aussi démontré que pendant les phases du migration en saison sèche (périple vers l'ouest, couloir vers l'ouest) le troupeau subit des reliefs complexes (complexité calculée sur la pente et inter visibilité) à la recherche de l'herbe la plus verte. Pendant la saison d'abondance (périple vers le sud), l'impact du relief sur le choix des routes devient critique, les troupeaux évitant le terrain difficile, malgré sa végétation relativement abondante. La méthode présentée dans cette étude permet de prédire de façon rapide et valable la route approximative des gnous en cours de migration dans des conditions climatiques diverses. [source]

Changes in miombo woodland cover in and around Sengwa Wildlife Research Area, Zimbabwe, in relation to elephants and fire

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2002
Isaac N. Mapaure
Abstract One of the consequences of impacts of elephants and fire on woodlands is a change in woody cover, which often results in major challenges for wildlife managers. Changes in miombo woodland cover in and around Sengwa Wildlife Research Area (SWRA) between 1958 and 1996 were quantified by analyzing aerial photographs. Woody cover in SWRA decreazed from 95.2% in 1958 to 68.2% in 1996, with a lowest mean of 62.9% in 1983. The annual absolute rate of woody cover change in SWRA increazed from ,1.1% per annum between 1958 and 1964 to a recovery of 1.6% per annum between 1993 and 1996, while the annual relative rate increazed from ,1.1% per annum between 1958 and 1964 to 3.3% per annum between 1993 and 1996. There was a strong negative correlation between elephant densities and woody cover in SWRA, suggesting that loss of woody cover was mainly due to elephants. Woodland recovery after 1983 was due to reductions in elephant populations through legal and illegal off-take and reductions in fire frequency. Surrounding areas experienced less woody cover losses than SWRA, mainly due to tree removal by locals whose densities increazed after the eradication of tsetse fly in the 1970s. Résumé Une des conséquences de l'impact des éléphants et des feux sur les forêts s'exprime par un changement du couvert ligneux qui pose souvent de fameux défis pour les gestionnaires de la faune. Les changements du couvert forestier à Miombo, qui sont survenus à l'intérieur et aux alentours de l'Aire de Recherche sur la Faune de Sengwa (SWRA) entre 1956 et 1996, ont été quantifiés grâce à l'analyse de photos aériennes. Le couvert forestier de la SWRA a diminué de 95.2% en 1958 à 68.2% en 1996, la moyenne la plus basse étant observée en 1983, avec 62.9%. Le taux annuel absolu de changement du couvert forestier dans la SWRA est passé de , 1.1% par an entre 1958 et 1964 à une restauration de 1.6% par an entre 1993 et 1996, tandis que le taux annuel relatif augmentait de , 1.1% par an entre 1958 et 1964 à 3.3% par an entre 1993 et 1996. Il existait une forte corrélation négative entre la densité des éléphants et le couvert forestier de la SWRA, ce qui laisse supposer que la perte de couvert forestier était due principalement aux éléphants. La restauration de la forêt après 1983 était due à des réductions des populations d'éléphants suite à des prélèvements, légaux ou non, et à une baisse de la fréquence des feux. Les zones adjacentes ont subi de moins fortes pertes du couvert forestier que la SWRA, et celles-ci étaient principalement dues à des coupes faites par les locaux dont la densité a augmenté suite à l'éradication de la mouche tsé-tsé dans les années 1970. [source]

Non-target impacts of poison baiting for predator control in Australia

MAMMAL REVIEW, Issue 3 2007
A. S. GLEN
ABSTRACT 1Mammalian predators are controlled by poison baiting in many parts of the world, often to alleviate their impacts on agriculture or the environment. Although predator control can have substantial benefits, the poisons used may also be potentially harmful to other wildlife. 2Impacts on non-target species must be minimized, but can be difficult to predict or quantify. Species and individuals vary in their sensitivity to toxins and their propensity to consume poison baits, while populations vary in their resilience. Wildlife populations can accrue benefits from predator control, which outweigh the occasional deaths of non-target animals. We review recent advances in Australia, providing a framework for assessing non-target effects of poisoning operations and for developing techniques to minimize such effects. We also emphasize that weak or circumstantial evidence of non-target effects can be misleading. 3Weak evidence that poison baiting presents a potential risk to non-target species comes from measuring the sensitivity of species to the toxin in the laboratory. More convincing evidence may be obtained by quantifying susceptibility in the field. This requires detailed information on the propensity of animals to locate and consume poison baits, as well as the likelihood of mortality if baits are consumed. Still stronger evidence may be obtained if predator baiting causes non-target mortality in the field (with toxin detected by post-mortem examination). Conclusive proof of a negative impact on populations of non-target species can be obtained only if any observed non-target mortality is followed by sustained reductions in population density. 4Such proof is difficult to obtain and the possibility of a population-level impact cannot be reliably confirmed or dismissed without rigorous trials. In the absence of conclusive evidence, wildlife managers should adopt a precautionary approach which seeks to minimize potential risk to non-target individuals, while clarifying population-level effects through continued research. [source]

Carnivore biodiversity in Tanzania: revealing the distribution patterns of secretive mammals using camera traps

ANIMAL CONSERVATION, Issue 2 2010
N. Pettorelli
Abstract Biodiversity monitoring is critical to assess the effectiveness of management activities and policy change, particularly in the light of accelerating impacts of environmental change, and for compiling national responses to international obligations and agreements. Monitoring methods able to identify species most likely to be affected by environmental change, and pinpoint those changes with the strongest impacts, will enable managers to target efforts towards vulnerable species and significant threats. Here we take a new approach to carnivore monitoring, combining camera-trap surveys with ecological niche factor analysis to assess distribution and patterns of habitat use of mammalian carnivore assemblages across northern Tanzania. We conducted 11 surveys over 430 camera-trap stations and 11 355 trap-days. We recorded 23 out of 35 carnivore species known to occur in Tanzania and report major extensions to the known distribution of the bushy-tailed mongoose Bdeogale crassicauda, previously thought to be rare. Carnivore biodiversity tended to be higher in national parks than in game reserves and forest reserves. We explored habitat use for seven species for which we had sufficient information. All species tended to be found near rivers and southern Acacia commiphora woodlands (except one mongoose species), and avoided deciduous shrubland, favouring deciduous woodland and/or open grassland. All species tended to avoid croplands suggesting that habitat conversion to agriculture could have serious implications for carnivore distribution. Our study provides a first example where camera-trap data are combined with niche analyses to reveal patterns in habitat use and spatial distribution of otherwise elusive and poorly known species and to inform reserve design and land-use planning. Our methodology represents a potentially powerful tool that can inform national and site-based wildlife managers and policy makers as well as international agreements on conservation. [source]

Genetic identification of source populations for an aquarium-traded invertebrate

ANIMAL CONSERVATION, Issue 1 2009
D. A. Weese
Abstract Increasingly, wildlife managers are turning to molecular genetics to aid in conservation efforts. While such approaches have been applied to large terrestrial and aquatic vertebrate species, their application to other traded organisms has not been extensively explored. Here, we examined the utility of these techniques for identifying source populations of aquarium ornamental invertebrates, using members of the Hawaiian atyid genus Halocaridina as a study system. These shrimps, restricted to anchialine habitats of the Hawaiian Islands, are popular in the aquarium trade due to their ability to survive in hermetically sealed containers for extended periods of time. However, commercial harvesting, coupled with habitat destruction and strong regional endemism, could lead to the depletion/extinction of unique populations. Because the land district of Kona, along the west coast of the island of Hawai'i, has the state's highest concentration of anchialine habitats, we hypothesized that commercially available Halocaridina originated from this region. To test this, mitochondrial cytochrome c oxidase subunit I gene sequences from 96 individuals, obtained from six vendors, were compared with 580 homologous sequences from previous studies covering the known distribution range of Halocaridina. Recovery of identical, regional-specific haplotypes, network analyses and statistical assignment tests identified these commercially acquired specimens as belonging to either the Kona, Ka',, (western and southern coasts, respectively, island of Hawai'i) or Kina'u (southern coast, island of Maui) genetic groups of these shrimps. Although 39 of the 96 individuals originated from the Kona genetic group as hypothesized, our finding that commercially available Halocaridina are from three genetic groups spanning two islands suggests that other populations also warrant potential management consideration. While this study represents the first application of molecular genetics in identifying source populations of aquarium ornamental species, we feel that these techniques are amenable more broadly as they are dependent on only a few caveats. [source]

A multi-attribute trade-off approach for advancing the management of marine wildlife tourism: a quantitative assessment of heterogeneous visitor preferences

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 2 2009
Christina A.D. Semeniuk
Abstract 1.Wildlife tourism can be prone to unmitigated development to promote visitor satisfaction that is all too often progressed at the cost of ecological integrity. A manager is thus faced with the dual task of enhancing the tourist experience and protecting the wildlife species. Accordingly, this mandate requires research into how tourists would respond to proposed wildlife-management plans. 2.This study examines the heterogeneity of tourist preferences for wildlife management at a stingray-feeding attraction in the Cayman Islands, using a latent class stated preference choice model. A sample of visitors to Stingray City Sandbar (SCS) evaluated hypothetical wildlife viewing experiences in a discrete choice experiment. Its scenarios were characterized by seven attributes such as animal-feeding and handling rules, ecological outcomes, social crowding, and management cost (defined as a conservation access fee). 3.The latent class segmentation identified two groups in the population: approximately 68% preferred the implementation of fairly strict management rules, while the other 32% valued more the maintenance of status quo with its intensive human , wildlife interactions. Despite the differences between the ,pro-management' and the ,pro-current' segments, both exhibited a preference for the continuation of feeding and handling the stingrays (albeit at different levels of intensity) suggesting that one effective way to implement any management actions is to alter the promotional and marketing strategies for SCS. Other survey questions on trip experience, conservation values, and socio-demographics were used to define these classes further, with the main distinguishing trait being the level of concern for potential impacts occurring at SCS. The discrepancies between the two segments became most obvious when calculating their respective market shares of support for alternative management strategies. 4.This approach to determining visitor preferences can help explain how the various segments will be affected by management options, and therefore can provide the basis for developing feasible strategies that will assist wildlife managers in maximizing tourist satisfaction while achieving wildlife-protection goals. Copyright © 2008 John Wiley & Sons, Ltd. [source]